Thermal packer construction



May 7, 1968 M. L. CROW ET AL THERMAL PACKER, CONSTRUCTION Filed Feb. 1, 1965 INVENTORS Morgan L. Crow Marion D. Kilgore Hurry E.-Simp'son ATTORNEY United States Patent 3,381,969 THERMAL PACKER CONSTRUCTION Morgan L. Crow, Marion D. Kilgore, and Harry E. Simpson, Dallas, Tern, assignors to Dresser Industries, Inc., Dallas, Tern, a corporation of Delaware Filed Feb. 1, 1965, Ser. No. 429,456 7 Claims. (Cl. 277-117) This invention is concerned with a packer for use in an oil or gas well, and is particularly concerned with a packer construction which is resistant to high tem peratures, and which is supported at each end thereof to thereby confine the packer material within a given longitudinal area when it is expanded into sealing engagement with the wall of the well casing.

The packer which is the subject matter of this invention is particularly designed for use in so-called thermal recovery methods employed in producing oil from wells and in injection of heated fluid into the well.

Thermal recovery is a method of injecting heated fluids, such as steam, water, or oil into a pipe extending into the well, or the employment of heat of combustion or other artificial heat production means in the producing formation to reduce the viscosity of the crude oil in the reservoir to such an extent as to permit the oil to flow from the reservoir into the well pipe, and therefrom to the surface, by normal production methods. Thereby large and valuable volumes of oil may be produced from reervoirs which were heretofore left in place by conventional producing practices.

The injected heat carrying fluid, such as steam, or other heat producing means produces a temperature of more than 600 F.

In order to minimize the heat loss, it is desirable to conduct injected fluid down the tubing string, and in order to confine the heated fluid for application to a localized reservoir area in the well bore, it is desirable to employ packers above and below same, between the tubing and the casing.

Conventional packers heretofore used are made of natural of synthetic rubber compositions and are elastic and deformable so that they can be expanded into sealing engagement with the casing after being lowered into the well. Such conventional packers are incapable of withstanding the high temperatures encountered in thermal recovery methods without deterioration and loss of sealing effectiveness.

The present invention is intended to provide a packer so constructed, and of such material, that it will withstand the high temperatures encountered in thermal recovery procedure, and which is supported and reinforced at the ends thereof so that it is confined within a given vertical area when expanded.

It is, therefore, a primary object of the invention to provide a packer construction made of sealing material which is resistant to high temperatures.

It is another object of the invention to provide a packer construction made of material which is resistant to high temperatures and enclosed within a confining wrapping or boot while it is being lowered into the well, which Wrapping or boot, is expandable to permit the packing material to be expanded.

A still further object of the invention is to provide such a heat resistant packing material which is supported and confined at each end thereof by deformable rings made of heat resistant material which is supported by deformable metallic support members which are radially expandable to prevent flowing and deformation of the packing over he supports at each end thereof.

Other and further objects of the invention will become apparent upon reading the detailed specification herein- 3,381,969 atented May 7, 1968 after following and by referring to the drawing annexed hereto.

A suitable embodiment of the invention is shown in the attached drawing wherein,

FIGURE I is a quarter sectional elevational view of the packer constructed in accordance with the invention, wherein said packer is in relaxed, unset condition,

FIGURE II is a fragmentary quarter sectional view of the lower end of the packer showing the relationship of the parts thereof when the packer is expanded and set against the wall of the casing,

FIGURE III is an exploded view of the metallic reinforcement plates or rings which are molded and embedded in the deformable support rings at each end of the packer assembly, and

FIGURE IV is a fragmentary cross-sectional elevational view of a modified form of end support construction for the packer material.

In the drawing numeral references are employed to designate the various parts shown in the drawing and like numerals indicate like parts throughout the various figures of the drawing.

The numeral 1 indicated a tubular mandrel on which the packer assembly is supported for lowering into the well, and while it is being set.

A tubular spacer collar 2 is movable downwardly with reference to the shell or tubular support member 3, and is secured to the upper packer head 3 by inter-engaging threads 4.

The head 3 has a shoulder 5 thereon which is engaged against a ring 6 welded to the tubular shell 8, about which the packing material is disposed.

The lower end of the packer assembly is supported by a lower support member or stufiing box 7, which is threadedly engaged at its upper end to the packer shell 8 by means of sealing companion threads 9.

The packing material 11 is abutted at its upper end to the scraper housing 7a, which is abutted against the shoulder 7b and at its lower end against scraper housing 70, which is supported on a pressure ring 121;, which is supported on a support ring 10 threadedly engaged at Illa to the lower end of the stuffing box 7.

Scraper rings 7d and 7e are carried by scraper housings 7a and 7c and are arranged to scrape against the surface of mandrel 1 when moved therethrough.

A plurality of pins 12 are fixed to pressure ring 12b and are slidably disposed in bores 12a provided in an extension ltlb on the support ring it). The pins 12 and ring lZb are urged relatively upwardly in the bores 12a by springs 13 as shown in FIGURE 1, to maintain the packing 11 in expanded position. The packing material 11 provides a slidable seal between the outer surface of the mandrel l and the packer assembly.

The main packing material per se .14 is formed by rectangular shaped asbestos braid which may be held together by suitable heat resistant plastic material. The packing material 14 may he wound about the shell 3 in a spiral or ring-like fashion if desired. After the packing material 14 is wound on the shell 8, an outer wrapping or boot 15, which is preferably formed from a strip or strips of cloth made of asbestos which may be treated and impregnated with heat resistant plastic material, is wrapped and wound about the material -14 to con-fine same while the packer assembly is being lowered into the well. The material of the wrapping is preferably impregnated or covered with an adhesive which coheres to multiple layers of the wrapping material as it is tightly wound about the packer material 1-4 to thereby form a cylindrical sleeve or boot which con-fines the packing material 14- of the packer in a package to contain same while running it to setting depth. Wrapping material 15 may be any type of flexible sheet material suitable for containing packing material 14.

Packing materials 14 is formed by braiding strands of asbestos material into a rectangular shape, and it may or may not be impregnated with a plastic or other binder material.

After the wrapping material or boot 15 has been so placed about the packing material 14 same may be secured and held in place by means of wires 16 wound about the ends thereof and tightly engaged therewith.

The packing element heretofore described is supported and confined at each end by cup-shaped back-up rings 17 which are molded of a relatively hard, deformable material, such as rubber or rubber composition which is reinforced with an asbestos or other heat resistant filler material, which may be in granular or powder form, so as to make it resistant to high temperature.

One or more cup-shaped metallic plates llg are preferably molded in the back-up rings 17 at the time they are made. Such plates 1% may be made of such diameters as to nest one within the other in the event a plurality of same are employed in a back-up ring 17.

Each plate 18 has a central passage lea therethrough through which the shell 8 may be extended, and includes an inwardly extending annular flange l9 thereabo-ut.

Spaced slots 2d are formed in the walls 181) of the plates 18 to provide spaced arms or petals 21 thereon. The plates 18 are preferably made of mild steel sheet metal which has a low yield and low tensile strength so that when pressure is exerted thereagainst, they will bend and deform permitting the arms 21 to move axially and outwardly as the packing material is deformed into engagement With the casing 23.

In the preferred form of the back-up ring 117, the metallic plates 13 are preferably nested one within the other as illustrated in FIGURES l and 2 and are arranged so that the slots 20 in one of the plates 13 are radially disaligned with respect to the slots 2i) in the adjacent plate 1 8 as illustrated in the exploded view of FIGURE 3. Molding the plates 18 in the rings hi7 provides assurance that the slots 20 will remain disaligned and that the plates 18 will be in the proper supporting position. Such radial disalignment provides a continuous annular support for the packing element when it is deformed into engagement with the casing 23.

When the spacer collar 2 is moved downwardly by downward pressure exerted thereagainst, the upper packer head 3 will move downwardly with reference to the shell 8, thereby compressing the packing material 14' to cause it to expand outwardly. The boot material 15 will expand as the packing material 14 is shortened and radially expanded until the packing material comes into sealing engagement .with the casing 26, as indicated in FIGURE II.

As the packing material 14 is axially shortened and/or compressed to achieve radial deformation or expansion, the back-up rings .17 will deform and expand also, as indicated in FIGURE II. As the rings 17 deform, flatten, and expand, the arms 21 on the plates 18 will be caused to deform and move outwardly toward the wall of the casing and as the rings 17 come into compressive engagement with the wall of the casing the outer end of the arms fi l will be pressed against the Wall of the casing, and ring 1 7, reinforced by plates 18, will substantially fill the annular space 23a between the packing assembly and the Wall of the casing to provide a cantilever support to prevent the extrusion of the rings 17, and the packing material 14 supported thereby, over the packer head 3 and lower support member 7 at each end of the packing material.

Therefore, the packing material 14 is confined within a substantially closed volume or area to provide for more effective sealing engagement with the wall of the casing.

The packing material ill i is made of such heat resistant Cit 1 material, as hereinbefore described, that it will withstand excessive heat encountered in thermal recovery and still maintain sealing engagement with the casing.

Furthermore, the packing material 14 is confined by an enclosure member or boot 15 while being run to provide for diametrical clearance from the wall of the casing 23, and is confined within a pre-determined longitudinal area or volume after it is expanded into sealing engagement with the wall of the casing 23.

In the modified form of FIGURE IV, the packing material 14- is supported at each end by braid 24 which is disposed within modified deformable plates 25 similar in construction and function to plates 18, and the whole assembly is confined Within a boot of sheet material 26 similar to sheet material 15 described above, about the ends of which are laced tie wires 27. The assembly shown in the modified form may be formed by laminating the element with cement and application of pressure. It is similar in function to the form heretofore described.

It will be understood that other and further forms of the invention may be devised without departing from the spirit and scope of the appended claims.

Having described our invention we claim:

it. In a well packer:

a tubular support member;

a generally cylindrical packing means disposed on said tubular support member, said packing means comprising a packer member formed from asbestos braid encircling said tubular support member,

a boot member formed from asbestos material encircling said packer member providing a protective cover thereover, and

means retaining said boot member over said packer member;

a back-up ring encircling said tubular support member adjacent each end of said packer member, each said back-up ring including a cup-like member of deformable material encompassing a portion of the exterior of said packing means, and

a deformable support ring supportingly engaging each said cup-like member, each support ring including an annular flange disposed generally transversely relative to the axis of and encircling said tubular support member, a wall portion extending generally parallel to the axis of said tubular support member and relatively toward said packing means;

an annular support member encircling said tubular support member adjacent one end of said packing means and supportingly engaging the adjacent one of said back-up rings; and,

an annular member encircling said tubular support member adjacent the other end of said packing means, said annular member being engageable with the other said back-up ring, said annular member and said annular support member being movable relatively toward each other to deform said packing means.

2. The well packer of claim 1 wherein said wall portion includes a plurality of arms extending generally parallel to the axis of said tubular support member.

3. In a well packer:

a tubular support member;

a generally cylindrical packing means disposed on said tubular support member, said packing means comprising a packer member formed from an elongated asbestos braid member of generally rectangular cross section spirally wound around said tubular support member,

a boot member formed from asbestos material encircling said packer member providing a protective cover thereover, and

means retaining said boot member over said packer member;

a back-up ring encircling said tubular support member adjacent each end of said packer member, each said back-up ring including a cup-like member of deformable material encompassing a portion of the exterior of said packing means, and

a plurality of metallic support rings molded into each said cup-like member, each support ring including an annular flange disposed transversely relative to the axis of said packing means and encircling said tubular support member, a plurality of arms extending generally perpendicularly relative to said flange and relatively toward said packing means, and each of said support rings adjacent a respective back-up ring being radially disaligned to form a continuous annular support for said back-up rings;

an annular support member connected with said tubular support member adjacent one end of said packing means and supportingly engaging the adjacent one of said back-up rings; and,

an annular member slidingly encircling said tubular support member adjacent the other end of said packing means, said annular member being engageable with and arranged to move the adjacent one of said back-up rings relatively toward said annular support member to deform said packing means.

4. The combination called for in claim 1 wherein the support rings are molded in the back-up rings.

5. The combination called for in claim 2 wherein a plurality of metallic support rings, nested one within another, are molded in each confining ring, said nested support rings being radially disaligned to form a continuous annular support for said back-up rings.

6. The combination called for in claim 1 wherein the boot member is formed from a strip of adhesive impregnated asbestos fabric wrapping material wound about the packing member; and said retaining means extends about the wrapping material at each end of the packing memher.

7. The combination called for in claim 1 wherein the asbestos braid is an elongaed member of generally rectangular cross section and is wound about the tubular support member in spiral fashion.

References Cited UNITED STATES PATENTS 1,318,352 10/1919 Cameron et al. 166-196 1,788,109 1/1931 Jett 277-299 X 2,112,545 3/1938 Roe 277-230 2,221,775 11/1940 Boynton 277-235 X 2,430,623 11/1947 Taylor et al. 277-235 X 2,698,269 12/1954 Sussen'bach 277-229 X 2,836,252 5/1958 Lane 277-116.2 2,885,009 5/1959 Baker 2771l6.2

FOREIGN PATENTS 953,670 3/1964 Great Britain. 621,527 6/1961 Canada.

LAVERNE D. GEIGER, Primary Examiner. J. S. MEDNICK, Assistant Examiner. 

1. IN A WELL PACKER; A TUBULAR SUPPORT MEMBER; A GENERALLY CYLINDRICAL PACKING MEANS DISPOSED ON SAID TUBULAR SUPPORT MEMBER, SAID PACKING MEANS COMPRISING A PACKER MEMBER FORMED FROM ASBESTOS BRAID ENCIRCLING SAID TUBULAR SUPPORT MEMBER, A BOOT MEMBER FORMED FROM ASBESTOS MATERIAL ENCIRCLING SAID PACKER MEMBER PROVIDING A PROTECTIVE COVER THEREOVER, AND MEANS RETAINING SAID BOOT MEMBER OVER SAID PACKER MEMBER; A BACK-UP RING ENCIRCLING SAID TUBULAR SUPPORT MEMBER ADJACENT EACH END OF SAID PACKER MEMBER, EACH SAID BACK-UP RING INCLUDING A CUP-LIKE MEMBER OF DEFORMABLE MATERIAL ENCOMPASSING A PORTION OF THE EXTERIOR OF SAID PACKING MEANS, AND A DEFORMABLE SUPPORT RING SUPPORTINGLY ENGAGING EACH SAID CUP-LIKE MEMBER, EACH SUPPORT RING INCLUDING AN ANNULAR FLANGE DISPOSED GENERALLY TRANSVERSELY RELATIVE TO THE AXIS OF AND ENCIRCLING SAID TUBULAR SUPPORT MEMBER, A WALL PORTION EXTENDING GENERALLY PARALLEL TO THE AXIS OF SAID TUBULAR SUPPORT MEMBER AND RELATIVELY TOWARD SAID PACKING MEANS; 